Refrigeration



Feb. 9, 1937.

A. LENNING 2,069,839

REFRIGERATION Filed Jan. 16, 1934 Y 2 Sheets-Sheet mv TQR 44W =4. ATTORNEY Feb.9,1937. A, LENWTIG 2,069,839

1 REFRIGERATION Filed Jan. 16, 1934 2 sheets -sheat 2 INVENT OR,

' pipes 2| and 22.

Patented Feb. 9, 1937 UNITED STATES PATENT OFFICE.

' REFRIGERATION Alvar Lenning, Stockholm, Sweden, assignor, by

mesne assignments, to Servel, Inc., Dover, Del" a corporation of Delaware Application January 16, 1934, Serial No. 706,804' I In Germany January 31, 1933 12 Claims.

to the accompanying drawings forming a part of this specification and of which:

Fig. l is a more or less diagrammatical view of an absorption type refrigerating system embody: ing the invention;

Fig. 2 is a cross sectional view taken on the line 2-2 of Fig. 1; V

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 1;

Fig. 4 shows another mbodiment of the invention;

Fig. 5 is a sectional view taken on the line 65 of Fig. 4; and p Fig. 6 is a sectional view taken on the line 66 of Fig. 4. v

' The system disclosed in Fig. l is of the general type shown in United States Patent No. '1,609,334 granted December 7, 1926-. The system is hermetically closed and operates due to the application of heat and includes a refrigerant such as ammonia; an absorption liquid such as water, and a pressure equalizing gasxsuch as hydrogen. The generator I0 is a horizontal cylinder'through which extends a flue I I and which is divided by a partition l2 into a weak liquor chamber l3 and a strong liquor chamber H. The generator maybe heated by an electric heating element inserted in the flue II or by a gas burner l5 projecting a flame into the flue ll orby any other suitable heating means.-

A thermo-syphon element l6 lifts ammonia vapor and strong solution (that is, absorption liquid having a relatively large content of refrigerant absorbed therein) into the upper part of a stand pipe H which is connected to the weak liquor chamber l3. The chamber I3 communicates with a pipe i8 which extends through a pipe i9 and is connected to the 'top of an absorber 20. A pipe 2| connects the bottom of the absorber with the pipe 19 and a pipe 22 connects pipe -I9 with chamber ll. There is a space between pipes l9 and lBwhich is connected to the This provides the usual liquid heat exchanger for transferof heat between weak liquor or absorption liquid flowing from the generator to the absorber. and strong liquor flowing from the absorber to the generator.

Ammonia vapor generated in chambers l3'and l4 passesupwardly through pipes l7 and i6 re- 5 spectively and through pipe 23 to a condenser 24 which may be cooled by water or by air. Fins 25 may be provided on the pipe 23 to provide cooling for rectification whereby entrained water vaporv is condensed and caused to flow back to the generator. Other kinds of rectifier or analyzer may be used. The ammonia .vapor liqueiies in the condenser and flowslthrough the seal 26 into the upperchamber 21 of a heat exchanger which forms a part of the evaporator designated .15 generally by reference character 23. The heat exchanger may be in the form of a round tube .29 as shown, or the tube may be of other cross section. as square. Fins 30 are provided on the outside of the tube or heat exchanger 29 to pro-v vide extended heat transfer surface. This member 29 may also be termed a high temperature evaporator section. The fins 30 provide an extended surface for exchange of heat between the surrounding atmosphere or body to, be cooled 25 and the liquid refrigerant within chamber ,21.

The member 29 is inside an insulated enclosure or refrigerator cabinet 3|. A horizontal partition 32 separates the member 29 into an- I upper chamber 21 and a lower chamber 33. The 30 high temperature evaporator section 29 may be formed as shown in Figs. 2 and 3 by-using a longitudinally split tube and placing the plate 32. between the halves of the tube and welding lon- I gitudinal edges at 34 and suitably closing the ends. 35

Welding is also provided in the ends so that the upper and lower chambers 21 and 33 are entirely hermetically sealed from each other. Plate 32 is formed with depending grooves or troughs 35 adapted to hold'pools of liquid. These consti- 40 the tute depending pockets which extend into low chamber 33.

Connected to the end of chamber 21 remote from the liquid inlet is a tube or pipe 36 which extends downwardly and again upwardly to con- 45 nect with the lower chamber 33. The tube 36 is an ice freezing evaporator section. The tube .may extend on the sides ofa housing-for ice trays and may be embedded in a metal structure so as to give good heat transfer between it and ,60

the ice trays. Means maybe provided within the tubular member 36 to hold liquid thereiir'in pools. Such means may consist of wire mesh or a'spiral wire or perforated plates. Connected to the bottom of the pipe 36 is a drain tube 33. 66

Outside of the space or body to 'be cooled is a gas heat exchanger 39 comprising an outer tube and an inner tube 40. The inner tube is connected with the absorber 23 and s through a partition 4| and communicates through tube 42 with the chamber 21 adjacent the liquid inlet 1 thereto. A tube 43 connects the outside space of the gas heat exchanger with the lower chamber 33 of the high temperature evaporator section. A conduit 44 connects the bottom of the outside chamber of the gas heat exchanger with the top of the absorber 20. Baflling means 45 is provided within the gas heat exchanger to provide good heat transfer between the gas inside and outside the inner tube 40. The tube 33 is connected to the inside tube 40 of the gas heat exchanger.

Other devices and controls may be added to the system for increasing the efficiency of the system in general.

The system operates as follows: Circulation between the generator and absorber is produced due to the'action of the thermosyphon element Hi. This element lifts liquid from chamber i4 to a higher level in pipe l'l than the connection of pipe It with the absorber,

thus providing a head for flow by gravity of the liquid from the -generator to the absorber. The liquid flows downwardly in pipe l'l through chamber l3, through pipe l3 and into the top of the absorber. Vapor is driven out in chamber I3 and passes in countercurrent to the downwardly flowing liquid in pipe ll. From the bottom of the absorber liquid flows through pipe 2|, pipe l9,

' pipe 22 and upwardly through element IE to liquid ammonia contained in the condenser flows into chamber 21 and rests on the upper surface of plate 32 and in the troughs formed by the depending portions 35. The conduit 33 is connected to chamber 21 above the top surface of plate 32.and acts as an overflow or a darn for maintaining a small height of liquid over the whole surface of the plate 32. Liquid flows from The absorber may be air cooled as shown, or maybe cooled by other means to carry away the rejected heat of absorption. From the upper part of the absorber the hydrogen, deprived of a sub stantial proportion of ammonia'gas and consequently constituting weak gas, flows through conduit 44 and upwardly within the outer space of the gas heat exchanger 39 and through pipe 43 into the lower chamber 33 of the high temperature evaporator-section. It will be appreciated that the rich gas passing through the wheat exchanger is cold whereas the gasin the-outer' chamber of the gas heat'exchanger is relatively warm. The cold gas in the inside passage cools the warm gas in the outside passage of the gas heat exchanger. v

The weak gas entering the chamber 33' is in direct contact with the bottom of the plate 32 and consequently is cooledby the liquid onplate 32.

this liquid being reduced in temperature due to p pe aooasso chamber 33 is a pre-cooler for the gas entering through pipe 36 and upwardly through the loops 33. The cooled gas flows downwardly thereof and enters the upper chamber 21. In

its flow through pipe 36 it is incontact with liquid ammonia and evaporation takes place at very low temperature. Thus the weak gas is cooled in two stages, the first of which is in the outside gas heat exchanger at a relatively high temperature and the second of which takes place in the chamber 33 at lower temperature. Thus the gas is cooled to very low temperature when it enters the ice freezing section of the evaporator, thus perperature can be obtained than if all the exchange of heat takes place outside the insulated enclosure. Any exchange of heat which isto take place at a temperature lower than the temperature of the food space advantageously is carried out within the food space. It is feasible to use the foregoing arrangement without the gas heat exchanger. In the'coil 38 the hydrogen is saturated with ammonia to the extentpermitted at the temperature prevailing and thereafter the,

gas and vaporous ammonia pass into the chamber 21 where further evaporationcan takeplace due to the higher temperature. -It will be seen that the construction of the member 29 formsa device for good heat transfer which is of simple construction and which provides gas tightness between the spaces on the opposite sides of the plate 32. I

In thearrangement shown in Figs. 4, 5, and 6, the member 23 is situated'below the coil 36. The weak gas passes fromthe absorber 23, which may be of the disc-containing typ as shown, into the space 33 on the 'under side of plate 32. Thence the gas passes upwardly to the top-of the evaporator freezing section 33 and downwardly therethrough to the chamber 21. The outlet from the condenser 24 is formed as a loop 46 disposed within chamber 21 and disposed just above the troughs in the plate 32. .The coil 43 is connected to a pipe 41 which is connected to the top of the evaporator section 33. In this embodiment,

evaporation in chamber 21. Thusthe lower liquid ammonia flows from the condenser downwardly to the-coil 46, through this loop, and upwardly through tube 41 and into the top loop of ice freezing section 33. This liquid refrigerant trickles downwardly within tube "and flows onto the plate 32. The inert gas likewise flows down wardly in tube 38. This flow is parallel, as distinct from counter-flow in Fig. 1. Since the member 29 is at relatively high temperature with respect to the coil 33, further evaporation takes place in chamber 21. The pipe or coil43 is in contact with evaporating liquid ammonia in chamber 21 and thus the ammonia liquid entering theevaporator is cooled. The weak gas is cooled by the contact with the under side of the plate 32. The weak'gas'inlet end of chamber 33 is. relatively warm and may be outside their:- sulated enclosure as shown. An additional gas heat exchanger may be used outside the insulatedenclosure. which may be a further exten-' weights of different vertically extending columns is not limited to the precise embodiments disclosed.

What I claim is: 1. In a refrigerating system employing a pressure equalizing gas, an evaporator having a low temperature ice freezing section and a high temperature section comprising a member having a horizontal partition dividing the same into an upper chamber and a lower chamber, the gas inlet to the ice freezing section being connected to said lower chamber, the gas outlet being connected to said upper chamber, means to supply liquid refrigerant to said upper chamber, means to withdraw rich gas from said upper chamber, and means to supply weak gas to said lower;

chamber. I

2. In a refrigerating system employing a pressure equalizing gas, an evaporator having a low temperature ice freezing section and a high temperature section, means to conduct the equalizing gas first through the ice freezing section and thence through the high temperature section, means to supply liquid refrigerant to the high temperature section, the ice freezing section being connected to the high temperature section to receive liquid therefrom by gravity flow, and means to exchange heat between gas flowin'g to the ice freezing section and liquidfin the high temperature section.

3. In a refrigerating system employing a pressure equalizing gas, an insulated enclosure, an evaporator in said enclosure having a low temperature section and a high temperature section, said high temperature section having separated spaces within the insulated enclosure, a gas heat exchanger outside said enclosure, an absorber, and means to conduct the pressure equalizing gas from the absorber to the gas heat exchanger, thence to one of said separated spaces, thence to the ice freezing section, thence to the other of said separated spaces, thence to said gas heat exchanger and back to the absorber, and means to supply liquid refrigerant to said space of the high temperature section receiving gas from the ice freezing section.

4. In a refrigerating system employing .a pres- "sure equalizing gas, means to maintain a pool of liquid refrigerant in heat exchange relation with the body to be cooled and in direct contact with rich gas, and means to conduct weak gas in indirect heat exchange relation with said pool, said pool maintaining means and said gas conducting means being so constructed and arranged that the pool is in at least as good heat transmitting relation with the body to be cooled as is the gas in the gas conducting means.

5. In a refrigerating system employing a pressure equalizing gas, a high temperature evaporator section having a trough adapted to hold liquid, means to supply liquid refrigerant to said trough, means to conduct rich gas above said trough, and means to conduct weak gas below said trough. v

6. In a refrigerating system employing a pressure equalizing gas, a high temperature evaporator section exposed to the body to be cooled and having a trough adapted to hold liquid, means to supply liquid refrigerant to sald trough, an ice freezing evaporator connected to receive over-' fiow liquid from said trough. and means to conduct gas underneath said trough, thence through said ice freezing sectionand thence over said trough.

' section and hence in direct contact with liquid in said holding means,

8. ma device ofthe character described, a pla having a groove, separate shells on opposite sides of and secured to said plate, said plate dividing the aggregate into two spaces, anevaporator section connected between said spaces, members for conducting gas to and from the devic'e,.and a member for conducting liquid refrigerant thereto.

9. In a refrigerating system employing a pressure equalizing gas, an insulated enclosure, an ice freezing evaporator section in said enclosure, a gas heat exchanger outsidesaid enclosure, a

plurality of fins in said enclosure, conduits for a weak and rich gas passing'through said fins, and

means to supply liquid refrigerant to the conduit for rich gas, said conduits being connected to said ice freezing evaporator section heat exchanger.

10. In a refrigerating system employing a presand said gas sureequalizing gas, an evaporator having a low temperature ice freezing section and a high temperature section, both saidsections beingin heat exchange relation with material to be cooled, means to conduct the equalizing gas in series first through the ice freezing section and then through the high temperature section, a condenser, means to conduct liquid from the condenser first in heat exchange relation with the high temperature section, then through the ice freezing'section and'then through the high temperature section, and means to exchange heat between gas flowing to the ice freezing section and liquid in the high temperature section.

' 11. In a refrigerating system employing a pressure equalizing gas, an evaporator having a low' temperature ice freezing section and a high temperature section, means to conduct the equalizing gas in series first through the ice freezing section and then through the high temperature section;-.

a condenser, means to conduct liquid from the condenser first in heat exchange relation with the high temperature section, thenthrough the a me' freezing section, and means to exchange heat between gas flowing to the ice freezing section and liquid in the high temperature section.

12. In a refrigerating system employing a pressure equalizing gas, an evaporator having a low temperature section and a high temperature section, said high temperature section having sep arated spaces, means to .conduct the pressure equalizing gas to one of said separated spaces, thence to the low temperature section, and thence to the other of said separated spaces, means to conduct'liquid refrigerant first through said second space and then through the low temperature section, and means to maintain a body of'liq'uidrefrigerant in said second space in thermal conductive relation with equalizing gas in said first space.

ALVAR LENNING. 

